I'm a bit desperate for help. I've had this cactus for 5 years already and never had an issue until recently. The base of the cactus is hard to the touch so I'm assuming it's healthy. However the top of the cactus is getting a little squishy and the tips are beginning to rot off. Does anyone have any suggestions as to what's going on. I've already had to cut some of the rot earlier this month. And now new rot is forming again. I've been having this issue for the past 3 weeks.

For care: I fertilized the cactus earlier this month with a cactus fertilizer and I'm acclimating it to the outdoor weather. I wait until the day gets above 60 and then I put the cactus outside until 7 when I bring it back in for the night. I water it maybe once a week or until the soil moisture meter says dry.

Cacti need very little fertilizer, and all the sun they can get. it's not happy being moved in an out. Where cactus live in the deserts, they get blazing sun during the day and very cold nights. If it has good drainage, and you're not freezing at night, it would be happier left out...maybe some overhead protection if you are getting a lot of rain.

I would stop the fertilizer and if your outdoor weather has no forecast of consecutive days of rain, then I would just let it enjoy the sun outdoors and all the air circulation it can get.

As mentioned already, if there will be too much rains, then it has to be in a protected overhang, or better yet, just keep it indoors by a south facing window and keep it there. Just do quarter turns to even out light distribution around the plant.